20 April 2016 Scripps ' Levels exceeded 409 parts per million for the first time in recorded history this month. ​​NOAA 10 Mar 2016 'Carbon dioxide levels are increasing faster than they have in hundreds of thousands of years. It’s explosive compared to natural processes'. Today’s human-made CO2 increase is 200 times faster, a dramatic rate compared to natural processes, Pieter Tans, leader of NOAA’s Global Greenhouse Gas Reference Network

Preindustrial ​concentration (WMO)CO2 278 ppm ​

Dec 2016. Press release and links CO2 rate of atmospheric CO2 increase is unprecedented in Earth history at 3 ppm/year 2015 and 2016.Atmospheric CO2 concentration history: it is also the highest in 15-20 million years.​

At over 400 ppm atmospheric CO2 is the highest in 15-20 million years2009 A. Tripati Coupling of CO2 ... of the Last 20 Million Years ​2013 Yi Ge Zhang A 40-million-year history of atmospheric CO2